This invention is related to tonneau covers for enclosing the cargo area of a vehicle such as a pickup truck, a boat or other structures with a flexible cover.
This invention is an improvement over U.S. Pat. No. 4,639,033 which issued Jan. 27, 1987 for a Tonneau Cover, and also an improvement over the aforementioned co-pending patent application. The aforementioned patent application and the patent disclosed a tonneau system for a basically non-resilient cover, having a J-shaped fastening member attached along the marginal edge of the cover. An L-shaped rail is mounted on the top flange of the pickup truck cargo box. The horizontal portion of the rail has a lip for receiving the J-shaped fastener. The J-shaped fastener is resilient so that it can be either snapped on or unwound from the lip. In addition, the resiliency of the fastener compensates for temperature changes causing expansion and contraction of the cover.
The cross-section of the rail has a vertical leg mounted adjacent the downwardly depending inside flange of the cargo box. The rail is held in place by a series of C-shaped clamps that receive the lower edge of a rail and the cargo box flange. A threaded fastener is passed through one leg of the C-shaped clamp to engage the cargo box flange to hold the clamp in position. The opposite leg of the clamp is adapted to receive the end of a slat which spans the cargo box area for supporting the tonneau cover in position.
U.S. Pat. Nos. 4,730,866 and 4,838,602 which issued respectively Mar. 15, 1988 and Jun. 13, 1989 to James A. Nett, disclose a supporting frame for a tonneau cover in which a rail is also mounted on the cargo box upper edge, adjacent the inside flange. The Nett rail includes upper and lower generally horizontal walls connected by a vertical web to form opposed inner and outer laterally-open slots. The outer slot slideably receives a snap fastener. The snap fastener mates with a complementary button on the tonneau cover. Nett employs a clamp for connecting the rail to the pickup truck sidewall. The clamp supports a bolt with a nut received in the inner slot of the rail. The clamp has a throat which receives the inside flange of the cargo box sidewall, and a lower lateral arm which engages the inside surface of the cargo box sidewall.